U.S. patent number 6,504,473 [Application Number 09/884,118] was granted by the patent office on 2003-01-07 for vehicle travel safety apparatus.
This patent grant is currently assigned to Honda Giken Kogyo Kabushiki Kaisha. Invention is credited to Shoji Ichikawa, Kenji Kodaka, Yoshihiro Urai.
United States Patent |
6,504,473 |
Ichikawa , et al. |
January 7, 2003 |
**Please see images for:
( Certificate of Correction ) ** |
Vehicle travel safety apparatus
Abstract
When a turning state of a subject vehicle is detected, the
action timing of the contact avoidance support device is slower
than when the turning state is not detected. When an action timing
determining part 22 estimates that there is the possibility of the
subject vehicle coming into contact with the vehicle in front and a
turning state of the subject vehicle is detected based on the
output from a transversal acceleration sensor S4, a changing rate
of the steering angle sensor S5, and a yaw rate sensor S3, a
compensation interval calculating part 23 calculates a compensation
interval depending on the size of the detected turning state (the
amount of the steering angle, the changing rate of the steering
angle, and the transversal acceleration). The action timing of the
brake actuator 12 is slowed by this compensation interval.
Inventors: |
Ichikawa; Shoji (Wako,
JP), Urai; Yoshihiro (Wako, JP), Kodaka;
Kenji (Wako, JP) |
Assignee: |
Honda Giken Kogyo Kabushiki
Kaisha (Tokyo, JP)
|
Family
ID: |
18686828 |
Appl.
No.: |
09/884,118 |
Filed: |
June 20, 2001 |
Foreign Application Priority Data
|
|
|
|
|
Jun 21, 2000 [JP] |
|
|
200-186719 |
|
Current U.S.
Class: |
340/435; 340/436;
340/903; 701/301; 701/70; 701/72 |
Current CPC
Class: |
B60T
7/22 (20130101); G01S 13/931 (20130101); G01S
2013/93271 (20200101); G01S 2013/932 (20200101); B60T
2201/02 (20130101); B60T 2260/09 (20130101); G01S
2013/9322 (20200101) |
Current International
Class: |
B60T
7/22 (20060101); G01S 13/00 (20060101); G01S
13/93 (20060101); B60Q 001/00 () |
Field of
Search: |
;340/435,436,903
;701/70,72,300,301 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wu; Daniel J.
Attorney, Agent or Firm: Arent Fox Kintner Plotkin &
Kahn, PLLC
Claims
What is claimed is:
1. A vehicle travel safety apparatus providing a object detecting
device that detects an object in front of the subject vehicle, a
relative velocity calculating device that finds the relative
velocity between the subject vehicle and the object based on the
result of the detection of said object detecting device, a contact
possibility estimating device that estimates the possibility that
said object and the subject vehicle will come into contact based on
the result of the calculation of said relative velocity calculating
device, and a contact avoidance support device that automatically
acts in a predetermined interval before contact when it is
estimated that there is the possibility of contact by said contact
possibility estimation device, and supports contact avoidance
between said object and the subject vehicle, wherein said vehicle
travel safety apparatus provides: a turning state detecting device
that detects the turning state of the subject vehicle, and a
compensating device that compensates said predetermined interval
when a turning state of the subject vehicle is detected by said
turning state detecting device.
2. A vehicle travel safety apparatus according to claim 1 wherein
said compensation device slows said predetermined interval.
3. A vehicle travel safety apparatus according to claim 1 wherein
said turning state detecting device detects a steering angle of the
steering due to the operation of the driver.
4. A vehicle travel safety apparatus according to claim 1 wherein
said turning state detecting device detects a changing rate of the
steering angle of the steering due to the operation of the
driver.
5. A vehicle travel safety apparatus according to claim 1 wherein
said turning state detecting device detects the transversal
acceleration of the subject vehicle.
6. A vehicle travel safety apparatus according to claim 1 wherein
said turning state detecting device detects at least two among the
steering angle, the steering angle changing rate, and the
transversal acceleration of the subject vehicle, and said
compensation device compensates said predetermined interval by
selecting the largest among compensation amounts of said
predetermined interval detected by said turning state detecting
device.
7. A vehicle travel safety apparatus according to claim 1 wherein
said contact avoidance support device is a vehicle brake
system.
8. A vehicle travel safety apparatus according to claim 1 wherein
said contact avoidance support device is a notification device
provided in the vehicle.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a vehicle travel safety
apparatus for avoiding contact with a object based on the
relationship of the relative positions of a vehicle detected ahead
of the subject vehicle by a object detection apparatus such as a
laser radar.
2. Description of Related Art
Conventionally, as disclosed in Japanese Unexamined Patent
Application, First Publication, No. Hei 8-240660 and Japanese
Unexamined Patent Application, First Publication, No. Hei 6-160510,
for example, a vehicle travel safety apparatus is known in which
electromagnetic radiation such as a laser is emitted towards a
vehicle traveling forward ahead of the subject vehicle, and based
on the result or the detection of the radar that receives the
reflected wave from the object of the vehicle and the like
positioned in front of the subject vehicle, detects an obstacle
traveling forward in front of the subject vehicle, and based on the
result of this detection generates an warning that brings about,
for example, an avoidance operation by the driver based on the
results of this detection, or automatically carries out a
controlling action to avoid contact with the obstacle.
In addition, among a travel safety apparatus of this type,
apparatuses are known that carry out the operation of warning about
a collision avoidance taking into account the speed of the subject
vehicle, the path of the subject vehicle, the relative distance
from the obstacle, the relative speeds, the relative angles and the
like.
However, in the conventional vehicle travel safety apparatus, it
cannot always be said that the elements of the condition of the
driver are sufficiently reflected in the operation control of the
travel safety apparatus, and thus, actually, there are cases in
which warnings and collision avoidance control are carried out even
in a situation where the driver is steering in advance to avoid an
obstacle such as a vehicle in front. Thereby, the operation * of
the travel safety apparatus may be complicated for the driver, and
unnecessary avoidance actions may occur for an obstacle that
presents no danger, thus inviting deterioration of the
drivability.
For example, a situation in which a driver is momentarily
distracted for about one .second for a safety check or speed check
can certainly occur during normal driving, and in this type of
situation, there are many times that the vehicle is traveling
almost perfectly straight. In addition, at this time, the steering
angle operated by the driver is small, the change of the steering
angle is low, and the transversal acceleration of the vehicle is
low. In such a situation, when the vehicle travel safety apparatus
determines that the collision danger is high, preferably warnings
and collision avoidance control is rapidly executed.
In contrast, when a steering operation is carried out that is of a
degree for cornering the vehicle or changing lanes, etc., generally
because the driver is driving while paying sufficient attention,
and thus in this situation when warnings and collision avoidance
control is carried out by the vehicle travel safety apparatus at
the same timing as in the situation of the momentary distraction
mentioned above, not only is this complicated for the driver, but
there may be a sense that the drivability has deteriorated.
SUMMARY OF THE INVENTION
In consideration of the conventional problems described above, it
is an object of the present invention to provide a vehicle travel
safety apparatus that can improve drivability by modifying the
avoidance action timing when the turning of the vehicle is
detected.
In consideration of the above problems, in a first aspect of the
present invention in it is an object of the present invention to
provide a vehicle travel safety apparatus (for example, the travel
safety apparatus 10 in the embodiment described below) providing a
object detecting device (for example, the radar apparatus S1 in the
present embodiment described below) that detects a object in front
of the subject vehicle (for example, the forward moving vehicle V11
in the embodiment described below), a relative velocity calculating
device (for example, the radar apparatus S1 in the embodiment
described below) that finds the relative velocity between the
subject vehicle (for example, the subject vehicle V10 in the
embodiment described below) based on the result of the detection of
the object detecting device, a contact possibility estimating
device (for example, the action timing determining part 22 in the
embodiment described below) that estimates the possibility that the
object and the subject vehicle will come into contact based on the
result of the calculation of the relative velocity calculating
device, and a contact avoidance support device (for example, the
brake actuator 12 and the warning apparatus 17 in the embodiment
described below) that automatically acts in a predetermined
interval before contact when it is estimated that there is the
possibility of contact by the contact possibility estimation
device, and supports contact avoidance between the object and the
subject vehicle, wherein a turning state detecting device (for
example, the yaw rate sensor S3, the transversal acceleration
sensor S4, and the steering angle sensor S5 in the embodiment
described above) that detects the turning state of the subject
vehicle, and a compensating device (for example, the steps S1 to
S11 in the embodiment described below) that compensates the
predetermined interval when a turning state of the subject vehicle
is detected by the turning state detecting device.
Due to this type of structure, when it is estimated that there is
the possibility that the subject vehicle may contact a object such
as a vehicle in front and when the turning state of the subject
vehicle is detected, the action timing of the contact avoidance
support device can be compensated, and action control of the travel
safety apparatus taking into account the elements of the state of
the driver is possible.
In addition, according to a second aspect of the invention, in the
invention according to the first aspect, the compensation device is
characterized in slowing the predetermined interval. Due to this
type of structure, when turning state is detected, the action of
the contact avoidance support device can be made slower than when a
turning state is not detected.
In addition, according to a third aspect of the invention, in the
invention according to the first and second aspects, the turning
state detecting device is characterized in detecting the steering
angle due to the operation of the driver. Due to this type of
structure, compensating the predetermined interval described above
depending on the size of the amount of the steering angle is
possible.
In addition, according to a fourth aspect of the invention, in the
invention according to any of the first through third aspects, the
turning state detecting device is characterized in detecting the
changing rate of the steering angle due to the operation of the
driver. Due to this type of structure, in the case that the
steering angle and the changing rate of the steering angle are both
detected by the turning state detection device, the detection of
the turning state can be carried out more precisely and the
compensation of the action timing of the contact avoidance support
device can be more precise.
In addition, according to a fifth aspect of the invention, in the
invention according to any of the first through fourth aspects, the
turning state detecting device is characterized in detecting the
transversal acceleration of the subject vehicle. Due to having this
type of structure, in the case that the transversal acceleration
and the steering angle or the transversal acceleration and the
changing rate of the steering angle velocity, or the transversal
acceleration and the steering angle and the changing rate of the
steering angle are detected by the turning state detection device,
the detection of the turning state can be more precise and the
action timing of the contact avoidance support device can be more
precisely compensated.
In addition, according to a sixth aspect of the invention, in the
invention according to the first and second aspects, the turning
state detecting device is characterized in detecting at least two
among the steering angle, the changing rate of the steering angle,
and the transversal acceleration of the subject vehicle, and
compensates the predetermined interval by selecting the largest
among the plurality of compensation amounts found by the turning
state detecting device. Due to having this type of structure, the
turning state can be detected more precisely and the action timing
of the contact avoidance support device can be compensated more
precisely.
In addition, according to a seventh aspect of the invention, in the
invention according to any of the first through sixth aspects, the
contact avoidance support device is characterized in being a
vehicle control system. Due to having this type of structure,
contact avoidance can be reliably carried out without depending on
the operations of the driver.
In addition, according to an eighth aspect of the invention, in the
invention according to any of the first through seventh aspects,
the contact avoidance support device is a notification device
provided in the vehicle. Due to having this type of structure, the
attention of the driver can be alerted so that he or she will carry
out the procedures for contact avoidance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a complete diagram showing the structure of a vehicle
travel safety apparatus device according to an embodiment of the
present invention.
FIG. 2 is a functional block diagram showing the vehicle travel
safety apparatus according to the present invention.
FIG. 3 is a diagram showing the relative positional relationship
between the subject vehicle and another travel vehicle.
FIG. 4 is a diagram showing an example of the map illustrating the
relationship between the changing rate of the steering angle and
the correction time of the vehicle travel safety apparatus
according to an embodiment of the present embodiment.
FIG. 5 is a diagram showing an example of the map illustrating the
relationship between the transverse acceleration and the correction
time of the vehicle travel safety apparatus according to an
embodiment of the present embodiment.
FIG. 6 is a flowchart showing the activation timing correction
processing of the vehicle travel safety apparatus according to an
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Below, a vehicle travel safety apparatus according to the present
embodiments will be explained referring to the figures. FIG. 1 is a
complete structural diagram of the vehicle V having the vehicle
travel safety apparatus 10 according to the embodiments of the
present invention installed, and FIG. 2 is a functional block
diagram of the travel safety apparatus 10 shown in FIG. 1.
As shown in FIG. 1, the vehicle V having installed the vehicle
travel safety apparatus 10 according to this embodiment provides
left and right front wheels WFR and WFR, which are the driving
wheels to which the drive power of the engine E is transmitted via
the transmission T, and the driven left and right rear wheels WRR
and WRL.
The brake pedal 11 operated by the driver is connected to the
master cylinder 13 via the brake actuator 12 that comprises an
electric control negative pressure booster.
The brake actuator 12 drives the master cylinder 13 by mechanically
doubling the leg power of the brake pedal 11, and at the same time
operates the master cylinder 13 by a signal from the electrical
control unit U independently of the operation of the brake pedal 11
during automatic control. Moreover, the input rod of the brake
actuator 12 is connected to the brake pedal 11 via a lost motion
mechanism, and even when the input rod is moved forward due to the
brake actuator 12 being activated by a signal from the electric
control unit U, the brake pedal 11 remains at the initial
position.
The master cylinder 13 is connected to the brake calipers 15FR,
15FL, 15RR, and 15RL respectively provided on the front wheels WFR
and WFL and the rear wheels WRR and WRL via the pressure adjuster
14. The pressure adjuster 14 will carry out antilock brake control
to suppress locking of the vehicle's wheels, and the oil pressures
in the brakes transmitted to the front wheels WFR and WRL and the
rear wheels WRR and WRL by a signal from the electric control unit
U are separately controlled.
In the electric control unit U, a radar apparatus S1 that transmits
an electromagnetic wave such as a laser or millimeter wave in the
forward direction of the vehicle body, and detects the relative
distance and the relative speed between the body of the car in
front and the subject vehicle based on the reflected wave, vehicle
wheel velocity sensors S2, . . . , S2 that respectively detect the
number of rotations of the front wheels WFR and WFL and the rear
wheels WRR and WRL, the yaw rate sensor S3 that detects the turning
of the vehicle V, the transversal acceleration sensor S4 that
detects the transversal acceleration of the vehicle V, a steering
angle sensor S5 that detects the steering angle due to the steering
operation of the driver are connected. Moreover, the radar
apparatus S1 realizes the object detection device and the relative
speed calculation device in the present invention, and the yaw rate
sensor S3, the transversal acceleration sensor S4, and the steering
angle sensor S5 each realize the turning state detection device in
the present invention.
The electric control unit U controls the operation of the brake
actuator 12 and the pressure adjustor 14 based on signals from the
radar apparatus S1 and each of the sensors S2 to S5, and at the
same time, controls the action of the warning apparatus 17
comprising a speaker, lamp and the like. Moreover, the brake
actuator 12 and the warning apparatus 17 each realize the contact
avoidance support device in the present invention.
In addition, as shown in FIG. 2, the electric control unit U
comprises a vehicle path estimating part 21, an action timing
determining part 22, a compensation time calculating part 23, and
an actuator command part 24.
The signal for the vehicle velocity output from the vehicle wheel
velocity sensor S2 and the signal for the turning of the vehicle V
output from the yaw rate sensor S3 are input into the vehicle path
estimating part 21, and this vehicle path estimating part 21
estimates that path on which the vehicle will advance in the
future.
The signal for the turning of the vehicle output from the yaw rate
sensor S3, the signal for the transversal acceleration output from
the transversal acceleration sensor S4, and the signal for the
steering angle output from the steering angle sensor S5 are input
into the compensation time calculating part 23, and this
compensation time calculating part 23 calculates the amount of
compensation of the action timing interval based on the information
from these sensors S3 to S5.
The action timing determining part 22 estimates the collision
danger based on the relative distance and the relative speed
between a physical object such as a vehicle in front and the
subject vehicle, the speed of the subject vehicle, and information
from the vehicle path estimating part 21 and the compensation time
calculating part 23, and determines the action timing. Moreover,
the action timing determining part 22 realizes the contact
possibility estimating device in the present invention.
The actuator command part 24 commands the brake actuator 12 with
the actuator output.
In the vehicle travel safety apparatus 10 structured as described
in FIG. 2, when the turning state of the vehicle is detected, the
execution timing of the contact avoidance processing (warning
processing and vehicle control processing) is modified depending on
the size of this turning state. When the driver is paying
sufficient attention during steering, for example, as described
above, the execution timing of the contact avoidance processing
slower than during the momentary distraction so that unnecessary
contact avoidance action is not taken, and at the same time,
drivability is improved.
When a turning state of a subject vehicle is detected, the action
timing of the contact avoidance support device is slower than when
the turning state is not detected. When an action timing
determining part 22 estimates that there is the possibility of the
subject vehicle coming into contact with the vehicle in front and a
turning state of the subject vehicle is detected based on the
output from a transversal acceleration sensor S4, a steering angle
changing rate sensor S5, and a yaw rate sensor S3, a compensation
interval calculating part 23 calculates a compensation interval
depending on the size of the detected turning state (the amount of
the steering angle, the changing rate of the steering angle, and
the transversal acceleration). And the action timing of the brake
actuator 12 is slowed by this compensation interval.
Below, the compensation of the execution timing will be explained
using the contact avoidance processing employing the warning
apparatus 17. First, the normal execution timing of the warning
apparatus 17 will be explained referring to FIG. 3.
Here, where the speed of the vehicle 10 is V0 (m/s), the speed of
the vehicle in front V11 is V1 (m/s), and the relative distance is
.DELTA.L (m), the electronic control unit U calculates the
necessary time (hereinafter referred to as the headway time) Th
(sec) for the vehicle 10 to arrive at the vehicle V11 in front
based on the relative relationships between the relative distance
.DELTA.L and relative speed .DELTA.V (.DELTA.V=V0-V1) detected by
the radar apparatus S1. In addition, normally the operation of the
warning apparatus 17 is controlled using the time in which this
headway time becomes equal to or less than the action timing
interval Ta (for example, 2 or 3 seconds) that is set in advance as
an action timing.
In contrast, in the case that the turning state is detected, the
action timing interval Ta is compensated depending on the size of
this turning state, and control is carried out such that the action
timing is slower than normal.
In this embodiment, the amount of the steering angle, the changing
rate of the steering angle, and the transversal acceleration due to
the operation of the driver are used as elements for detecting the
turning state. In addition, based on these respective elements, the
compensation with respect to the action timing interval Ta is
calculated, the largest compensation amount DT among these is used,
and the action timing interval Tar after compensation is calculated
(Tar=Ta-DT).
First, in the case that the compensation amount DTd.theta. of the
action timing interval Ta is calculated from the changing rate of
the steering angle, the electronic control unit calculates the
changing rate of the steering angle .DELTA..theta. (rad/sec) from
the amount of the steering angle .theta. detected by the steering
angle sensor S5, and based on the absolute value of the calculated
steering angle changing rate .DELTA..theta., the compensation
amount DTd.theta. is calculated referring to the steering angle
changing rate/compensation time map. FIG. 4 is an example of the
steering angle changing rate/compensation time map, and the
compensation amount DTd.theta. is set so as to increase as a first
order function in accordance with the increase in the absolute
value of the changing rate of the steering angle .DELTA..theta.,
and the upper limiting value is set to 1.0 (sec). In the map shown
in FIG. 4, for example, the compensation amount when the changing
rate of the steering angle .DELTA..theta.=.pi.(rad/sec) is
DTd.theta.=0.5 (sec).
In addition, in the case that the compensation amount DTyG of the
action timing interval Ta is calculated from the transversal
acceleration, the electronic control unit U calculates the
compensation amount DTyG referring to the transversal
acceleration/compensation time map based on the absolute value of
the transversal acceleration Yg (m/sec.sup.2) detected by the
transversal acceleration sensor S4. FIG. 5 is an example of a
transversal acceleration/compensation time map, and the
compensation amount DTyG is set so as to increase as a first order
function according to the increase in transversal acceleration Yg,
and the upper limit value is set to 1.0 (sec). In the map shown in
FIG. 5, for example, the compensation amount when the transversal
acceleration Yg=0.5 (sec) is DTyG=1.0 (sec).
Moreover, the following relationship holds between the transversal
acceleration Yg (m/sec.sup.2) and the vehicle speed V (m/s) and the
cornering radius R(m):
In addition, because the relationship between the amount of the
steering angle .theta. (rad) and the cornering radius R(m) is an
inverse proportion, Eq. 1 can be represented by the following
equation:
In addition, by setting the constant .alpha. such that the
relationship between the amount of the steering angle .theta. and
the compensation time is the same as the relationship between the
transversal acceleration Yg and the compensation time, the
relationship between the amount of the steering angle .theta. and
the compensation time (the compensation amount DT.theta.) can be
represented by the following equation:
Using this equation, the electronic control unit U calculates the
compensation amount DT.theta. of the action timing interval Ta from
Eq. 3 based on the amount of the steering angle .theta. detected by
the steering angle sensor S5. Moreover, in this case, the upper
limit value of the compensation amount DT.theta. is set to 1.0
(sec).
Additionally, in this embodiment, the compensation amount DT.theta.
calculated based on the amount of the steering angle .theta., the
compensation amount DTd.theta. calculated based on the steering
angle changing rate .DELTA..theta., and the compensation amount
DTyG calculated based on the transversal acceleration Yg are
compared, and using the largest compensation amount among these,
the action timing interval Tar after compensation is calculated
from the above equations, and the operation of the warning
apparatus 17 is controlled using the time in which the above
described headway time Th becomes equal to or less than the action
timing interval Tar after compensation as the action timing.
According to the travel safety apparatus 10 of the present
invention, when it is estimated that there is the possibility that
the vehicle V10 will contact the object such as the vehicle in
front V11 and the turning state of the vehicle is detected, the
action timing of the warning apparatus can be compensated so as to
slow down depending on the size of this turning state, and thus
when the driver is driving by steering while paying sufficient
attention, such as during cornering or while changing lanes,
discomfort in driving contributed by unnecessary activation of the
warning apparatus 17 can be prevented, the warning apparatus 17 can
be activated only when a warning is actually necessary, and the
precision of the execution of the warning apparatus 17 and the
drivability improve.
In the travel safety apparatus 10 according to the present
embodiment, the compensation amounts DT.theta., DTd.theta., and
DTyG are respectively calculated based on the three turning state
detection elements, the amount of the steering angle .theta., the
changing rate of the steering angle .DELTA..theta., and the
transversal acceleration Yg, and using the largest compensation
amount among these, the action timing of the warning apparatus 17
is compensated so as to be slowest, and thus the execution
precision of the warning apparatus 17 and the drivability are
dramatically improved.
Next, the action timing compensation processing of the vehicle
travel safety apparatus 10 in this embodiment will be explained
referring to the flowchart in FIG. 6.
First, in step S101, the compensation amount DT.theta. is
calculated using Eq. 3 based on the amount of the steering angle
.theta. detected by the steering angle sensor S5.
Next, the flow proceeds to step S102, and the compensation amount
DTd.theta. is calculated referring to the changing rate of the
steering angle/compensation time map shown in FIG. 4 based on the
steering angle changing rate .DELTA..theta..
Next, progressing to step S103, it is determined whether or not the
compensation amount DT.theta. calculated based on the amount of the
steering angle .theta. is larger than the compensation amount
DTd.theta. calculated based on the steering angle changing rate
.DELTA..theta..
In the case that the determination in step S103 is positive, the
flow proceeds to step S 104, and the compensation amount DTyG is
calculated referring to the transversal acceleration/compensation
time map shown in FIG. 5 based on the transversal acceleration Yg
detected by the transversal acceleration sensor S4.
Next, the flow proceeds to step S105, and it is determined whether
or not the compensation amount DT.theta. calculated based on the
amount of the steering angle .theta. is larger than the
compensation amount DTyG calculated based on the transversal
acceleration Yg. In the case that the determination in step S105 is
positive, the flow proceeds to step S106, and the compensation
amount DT.theta. calculated based on the amount of the steering
angle .theta. will serve as the compensation amount DT. This is
because as a result of comparing the three compensation amounts
DT.theta., DTd.theta., and DTyG, compensation amount DT.theta. is
determined to be the largest.
In contrast, in the case that the determination in step S105 is
negative, the flow proceeds to step S107, and the compensation
amount DTyG calculated based on the transversal acceleration Yg
will serve as the compensation amount DT. This is because as a
result of comparing the three compensation amounts DT.theta.,
DTd.theta., and DTyG, compensation amount DTyG is determined to be
the largest.
In contrast, in the case that the determination in step S103 is
negative, the processing proceeds to step S108, and the
compensation amount DTyG is calculated referring to the transversal
acceleration/compensation time map shown in FIG. 5 based on the
transversal acceleration Yg detected by the transversal
acceleration sensor S4.
Next, the flow proceeds to step S109, and it is determined whether
or not the compensation amount DTyG calculated based on the
transversal acceleration Yg is larger than the compensation amount
DTd.theta. calculated based on the changing rate of the steering
angle steering angle changing rate .DELTA..theta.. In the case that
the determination in step S109 is positive, the flow proceeds to
step S107, and the compensation amount DTyG calculated based on the
transversal acceleration Yg will serve as the compensation amount
DT. This is because as a result of comparing the three compensation
amounts DT.theta., DTd.theta., and DTyG, the compensation amount
DTyG is determined to be the largest.
In contrast, in the case that the determination in step S109 is
negative, the flow proceeds to step S110, and the compensation
amount DTd.theta. calculated based on the changing rate of the
steering angle .DELTA..theta. will serve as the compensation amount
DT. This is because as a result of comparing the three compensation
amounts DT.theta., DTd.theta., and DTyG, the compensation amount
DTd.theta. is determined to be the largest.
After each of step S106, step S107, and step S110, the flow
proceeds to step S111, the action timing interval Tar after
compensation is calculated (Tar=Ta-DT), and the present routine
stops for the time being.
Moreover, the vehicle travel safety apparatus according to the
present invention is not limited to the embodiment described above,
and for example, the transversal acceleration can be calculated
from the subject vehicle speed and the yaw rate of the subject
vehicle.
In addition, in the embodiment described above, the action timing
interval Ta of the warning apparatus 17 was explained as an
example, but the same compensation control is possible for the
action timing interval Tb of the brake actuator 12. In this case,
in the case that action timings Ta and Tb are compensated, the
action timing interval Ta of the warning apparatus 17 can be set
equal to or greater than the action timing interval Tb of the brake
actuator 12 (Ta.gtoreq.Tb). Thereby, the attention of the driver
can be alerted by the warning apparatus 17, and in the case that in
spite of this the possibility of contact cannot be avoided, the
contact avoidance can be carried out by automatic control.
In addition, in the embodiment described above, three elements for
detecting the revolution condition were used: the amount of the
steering angle, the changing rate of the steering angle, and the
transversal acceleration, and from among the compensation amounts
DT calculated based on each of these elements, the largest
compensation amount DT was found, and based on this compensation
value, the action timing interval is compensated. However, as
elements for detecting the rotation state, among the three
elements, two elements (the amount of the steering angle and the
changing rate of the steering angle or the amount of the steering
angle and the transversal acceleration or the changing rate of the
steering angle and the transversal acceleration) can be used, and
the action timing interval calculated using the largest among the
compensation values DT calculated based on each of the two elements
as the compensation amount DT. Alternatively, as elements for
detecting the rotation state, among the three elements, one element
can be used, and the action timing interval compensated using the
compensation amount DT calculated based on this element.
In addition, in the embodiment described above, as a brake
actuator, the electric control negative pressure booster was used,
but this is not limited thereby, and for example, an
electromagnetic proportional valve can be provided.
As explained above, according to a first aspect of the present
invention, when it is estimated that there is the possibility that
the subject vehicle may contact a object such as a vehicle in
front, the turning state of the subject vehicle is detected, and
the action timing of the contact avoidance support device can be
compensated, action control of the travel safety apparatus taking
into account the elements of the state of the driver is possible,
and thus there is the effect that the contact avoidance can be made
more effective.
According to a second aspect of the invention, when a turning state
is detected, the action of the contact avoidance support device can
be made slower than when a turning state is not detected, and thus
when the driver is driving by steering while paying sufficient
attention, unnecessary activation of the contact avoidance support
device can be prevented, which device that there are the effects
that the precision of the execution of the contact avoidance can be
increased and the drivability can be improved.
According to a third aspect of the invention, compensating the
predetermined interval described above depending on the size of the
amount of the steering angle is possible, and thus there is the
effect that the contact avoidance can be made more effective.
According to the fourth aspect of the invention, compensation of a
predetermined interval depending on the size of the steering angle
change is possible, and thus there is the effect that the contact
avoidance can be made more effective. In particular, in the case
that the steering angle and the changing rate of the steering angle
are both detected by the turning state detection device, the
detection of the turning state can be carried out more precisely
and the compensation of the action timing of the contact avoidance
support device can be more precise, and thus there are the effects
that the precision of the execution of the contact avoidance can be
increased and the drivability further improved.
According to a fifth aspect of the invention, compensation of a
predetermined interval depending on the size of the transversal
acceleration is possible, and thus there is the effect that the
contact avoidance can be made more effective. In particular, in the
case that the transversal acceleration and the steering angle or
the transversal acceleration and the steering angle changing rate,
or the transversal acceleration and the steering angle and the
steering angle changing rate are detected by the turning state
detection device, the detection of the turning state can be more
precise, and thus there are the effects that the precision of the
execution of the contact avoidance can be increased and the
drivability further improved.
According to a sixth aspect of the invention, the turning state can
be detected more precisely and the action timing of the contact
avoidance support device can be compensated more precisely, and
thus the precision of execution of the contact avoidance can be
further increased and the drivability can be further improved.
According to a seventh aspect of the invention, contact avoidance
can be reliably carried out without depending on the driving
operations, and thus there is the effect that the safety is
increased.
According to an eighth aspect of the invention, there is the effect
that the attention of the driver can be attracted such that he or
she carries out the procedures for contact avoidance.
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